Multiple Impact Syndrome is the prolonged manifestation of symptoms after one has sustained multiple concussions over a period of years. The brain loses its ability to recover from some of the injuries. I have MPI and will never regain my short term memory functions and some other functions.

Subconcussive impacts are those repeated dings, usually daily, due to football practice and soccer heading drills. There are no immediate concussion symptoms but the accumulation of small physical stresses can lead to long term symptoms.

Being worried about little head bumps is counter productive. The stress is not good for a healthy brain.